Bull trout (Salvelinus confluentus) swimming in the Bighorn Creek, in the Wigwam River drainage in British Columbia. This is one of the last, best places for spawning of the vulnerable (ICUN) and federally-threatened bull trout, and is part of the Kootenay River system, which sees an annual migration of bull trout from Lake Koocanusa, some fifty miles away. The fish prefer very cold water of 40 degrees or so in order to spawn, and the springs in this area provide that. Ram Creek flows into the Wigwam, and between the two of them they support some 5,000 bull trout.
A fisheries technician for dam owner Avista, uses a radio antenna to track tagged bull trout in a stream that feeds into Noxon Reservoir. Biologists track a handful of tagged fish daily to try and learn about their migratory movements, which a series of dams on the nearby Clark Fork River have severely impeded.